Former prime minister Kevin Rudd is ignoring media requests and has cancelled an official appearance during his trip to New York City.

Mr Rudd was expected to attend the dinner this morning as part of his involvement with the Australian-American leadership dialogue.

Just hours beforehand he told organisers he would be unlikely to take part.

But this lunchtime Mr Rudd popped up on social networking service Twitter, tweeting about his "useful day at the UN", and singing the praises of UNICEF.

"Useful day at the UN yesterday, meeting with Secretary General and today met with the head of UNICEF," he wrote.

"Therese is a patron of UNICEF Australia's work on maternal and child health.

"UNICEF does fantastic work worldwide in reducing deaths in childbirth in the poorest countries."

The dinner cancellation came as his successor Julia Gillard faced renewed questioning about whether or not she had agreed a deal with Mr Rudd on the night before she replaced him as Labor leader.

Press gallery veteran Laurie Oakes quizzed Ms Gillard on claims that Mr Rudd had wanted to stay on as PM but promised he would quit in Ms Gillard's favour if the polls failed to improve before a mooted October election.

He asked Ms Gillard if it was true she had agreed to the deal but then changed her mind after her backers told her she had the numbers for a challenge

Mr Rudd and his wife are staying with Australia's ambassador to the UN Gary Quinlan at his official residence.

The two men are long-time friends.

Mr Quinlan told the ABC he did not have the details of Mr Rudd's movements.

Mr Rudd arrived in New York yesterday and met with UN secretary-general Ban Ki-moon.

The former prime minister has ignored all media requests for interviews.